Similar iq.

18-135mm STM lens only necessary for t4i, which has continuous auto focus function for video.
The image quality are very similar. T4i wins in easy of handling thanks to its touch screen and new features. 60d has better build quality.

How They are Similar

‘Similar’ APS-C 18m sensor
Tilt out screen
Only take SD cards
Both shoot around 5 fps

How They are Different

T4i has a touch screen
T4i autofocus for video
T4i can record up to 30 minutes creating multiple files
60D has an aperture wheel
60D have kelvin adjustment
60D has 3rd stop ISO adjustments
Battery
HDMI outputs are different
60D has a top LCD display
60D has a bigger grip
T4i has a Digic 5 processor while the 60D has a Digic 4
T4i has a stereo mic, 60D is mono
Eye-level pentaprism for 60D 96%, and Eye-level SLR (with fixed pentamirror) for T4i 95%. Pentaprisms are brighter than pentamirror. I could not tell the difference, and one didn’t seem brighter than the other.
1/8000 shutter for the 60D, 1/4000 for T4i
60D has an electronic level
60D is Aluminum and polycarbonate resin with glass fiber, and the T4i is Stainless Steel and polycarbonate resin with glass fiber.
60D has a spring in the SD door
Mode dial lock on 60D
60D can run Magic Lantern, the T4i you will have to wait for the first firmware update
So basically the two important new features, a touch screen and the new Hybrid AF system uses new STM lenses to automatically focus in video .